The present invention relates to a fabricating method of an aluminum matrix composite, more particularly, to a fabricating method of an aluminum matrix composite by means of simply heating a mixture of aluminum powder and a ceramic reinforcing phase under a nitrogen or an ammonium atmosphere (10-100 vol. %) whose concentration may be adjusted by mixing with non-oxidizing gases such as argon or hydrogen, and an aluminum matrix composite fabricated by said method.
Metal matrix composites (MMCs) reinforced by various forms of ceramic phases such as particles, whiskers and fibers etc. have much better characteristics than the respective individual constituent materials because they combine the characteristics of the metal matrix (ductility and toughness) and the characteristics of ceramic materials (high strength and stiffness). Especially, since the overall properties of the two materials are very different (such as physical, thermal, electrical and mechanical properties etc.), in particular, MMCs have the advantage of possessing a possibly wide spectrum of properties between metals and ceramics. This is because a virtually countless number of combinations are possible if one changes the metal matrix and the type, size, form and relative amount of the reinforcing phase. Therefore through an appropriate combination of such parameters, properties of MMCs can be tailored to satisfy the conditions of their final usage.
Recently through significant advances in MMCs, their applications can be found in land transportation (automobiles and railways), thermal management, aerospace and industrial etc. From recreational to basic industry, not only are they being applied in hi-tech industries but also in our everyday life.
Among various metals applied, nearly 70% of all commercial MMCs in the global market are Al MMCs. Typical commercial methods of manufacturing them are stir casting, liquid phase infiltration and powder metallurgy. MMCs are made by incorporating a ceramic reinforcing phase into a metal matrix. However, since the overall properties of the two materials are greatly different, it is difficult to incorporate the reinforcing phase into the metal matrix. Therefore, in order to overcome this problem, a method involving high energy mixing is performed (e.g. stir casting), or a method involving infiltration of a melt under high pressure into a preform is conducted (e.g. liquid phase infiltration) or a method involving mixing powders then consolidating them under pressure followed by sintering is performed (e.g. powder metallurgy). Nevertheless, all these processes require additional equipment to manufacture MMC products and therefore contribute to the overall cost as cost increasing factors.
In addition, the processes mentioned above have limitations in types of reinforcing phases and volume fractions that could be applied. Ironically, the respective additional processes can also cause detrimental effects to the properties of the final product.
Although, the global market for MMCs, unlike in the past, is expected to grow 6.6% annually by 2019 through technical innovation, its market size is actually still relatively small compared to other materials. One of the most important reasons for this is that the cost competitiveness of MMCs is still fairly low with respect to other competing materials. In order to overcome such problems, research on low cost large output processing technologies is being performed actively around the world.
Therefore, if a simpler process that did not need additional equipment like the conventional processes were to be developed and thus be more cost competitive, it can provide the opportunity to greatly expand the application of MMCs.
The present invention regards to a method of fabricating Al composites using an absolutely new concept that does not require complex equipment.